This looks very strange how your continentStore.loadItem() calls _store.newItem() 500 times. !TreeStoreMOdel responds to every new item by requerying the list of children for that item (see TreeStoreModel.onNewItem). So, you should stop calling _newItem() from loadItem().

Also, eventually you should stop using the deprecated TreeStoreModel and use ObjectStoreModel instead.

Because we get so many tickets, we often need to return them to the initial reporter for more information. If that person does not reply within 14 days, the ticket will automatically be closed, and that has happened in this case. If you still are interested in pursuing this issue, feel free to add a comment with the requested information and we will be happy to reopen the ticket if it is still valid. Thanks!